by Dava Sobel
And the wakened echoes, glancing
From the mountain, rocky browed,
And the lights in water dancing—
Each my wandering sense entrancing,
Tells me back my thoughts aloud,
All the joys of Truth enhancing
Crushing all that makes me proud.
—James Clerk Maxwell, “Reflex Musings:
Reflections from Various Surfaces”*
Magellan’s radar images look like nighttime aerial reconnaissance photos, except that instead of providing a visual record, their blacks and whites reflect the varying textures of Venus’s exposed beauty: Hundreds of thousands of small Venusian volcanoes pop out as bright (rough) bumps against the dark (smooth) background of the plains. On the flanks of giant volcanoes, bright (new) layers of lava drape themselves over the dark (old) flows. Mountainsides glittering in radar brightness seem to boast slopes coated with a veneer of reflective metal, perhaps fool’s gold, that adheres to Venusian rock at the cooler temperatures a few thousand feet up.
Etched in these images, Venus reveals her unique oddities, such as overlapping “pancake dome” volcanoes that rise from surprisingly round bases to flat or softly mounded tops, and her numerous “coronae,” or sets of concentric rings that ornately surround so many of her domes, depressions, and crowds of small volcanoes. Rushing streams of lava dug the long riverine channels that wind across her ample plains. On her high plateaus, tectonic folding and faulting have decorated several thousand square miles to look like crazy-tiled floors, now called “tesserae.” Evocative patterns in Venus’s extruded lava and cracked ground that reminded scientists of sea anemones and spider webs have become “anemone volcanoes” and “arachnoids.”
After amassing their gallery of radar portraits, Venus specialists enhanced many of the images with color for improved resolution. They chose a fire-and-brimstone palette, beginning with the russet hue of the first photos taken by the Russian Venera spacecraft, continuing the theme in ochre, umber, sienna, copper, pumpkin, and gold. The vibrant colors suit the seared scenery, the rock that spewed forth as lava and still retains its near-plastic consistency, the massifs ascending to altitude without ever hardening harder than taffy. Bright shades befit the youthful visage of a planet that only recently (within the last half billion years) repaved itself in veritable floods of lava, which welled up and covered over almost every vestige (about 85 percent) of her ancient past.
Relatively few craters mar the new face of Venus, since the rate of cratering over these past 500,000 years is much reduced from the Solar System’s earliest days. Many small would-be intruders are vaporized on their way through the thick atmosphere, never to touch down, so that only the very largest impactors reach the surface intact. These collisions eject copious debris, yet all the rubble hugs close around the crater margins in neat festoons, as though contained there by the heavy air. The atmosphere likewise may have soothed the fury of Venusian volcanoes, compelling their expelled lava to seep and pour rather than erupt with explosive force.
Although Magellan witnessed no outflows over the years it observed Venus, some of her volcanoes may well be active. Right now, sulfurous gases hissing from Venusian fumaroles could be making their way up to the clouds above the planet, to augment them and sustain them, and thereby ensure the enduring brightness of Venus to our eyes. That fair appearance of unassailable purity once made Venus the darling of Romantic poets, whose words still best express her effect on the night’s blue velvet—“a joy forever,” as Keats said, “a cheering light/Unto our souls.” But new odes to Venus inspired by informed impressions of her savage beauty will have to tap sprung rhythms to describe it, and perhaps shun rhyme.
*The faintest stars visible to the naked eye are those of the sixth magnitude. First-magnitude stars are one hundred times brighter, and the very brightest stars rank at zero, or even –1. Bright Venus reaches –4.6, the full Moon –12, and the Sun –27.
*Holmes, a practicing physician and professor of anatomy at Harvard, as well as a poet, essayist, novelist, and amateur astronomer, wrote this poem after seeing a transit of Venus on December 6, 1882.
*The spacecraft honors Portuguese explorer Ferdinand Magellan, who planned the first circumnavigation of the Earth, and set out from Spain with five ships in 1519. Although Magellan died en route during a battle in the Philippines, one of his ships and a skeleton crew completed his mission, returning to Spain in 1522.
*The physicist wrote poems as a hobby, and saw forty-three of them published.
GEOGRAPHY
To draw the map of the world, begin at the center of the universe. This is where the astronomer Ptolemy takes up his geography project in the second century. Having already compiled his famous astronomy book, the Almagest, in the year 150, Ptolemy turns to the problem of arranging the earth’s eight thousand known localities in their proper relative positions. He can hardly have attempted mapping the ground before mastering the sky, because he requires the Sun and stars to guide the placement of each earthly feature. Without astronomy, Ptolemy knows there can be no geography.
Ideally, Ptolemy wishes to watch which way his shadow falls at noon on certain days of the year in distant capitals, see what constellations appear there at night from one season to the next, and note whether the planets pass directly overhead, or ascend only partway up the sky. Alas, he cannot venture so far. Although the celestial spheres routinely rotate the Sun, Moon, planets, and a thousand stars into his view, the ends of the earth elude him.
Rooted at his map table in Alexandria, Ptolemy explores the world through the works of previous—often careless—cartographers and a babble of travelers’ reports. Thus he hears the distance from Libya to the country “where the rhinoceros congregate” variously described by Roman army officers as a forced march of three—or four—months’ duration, with no reference to the number of days spent resting en route or even the precise direction taken.
If only those favored with travel opportunities, laments Ptolemy in Geographia, his how-to book for mapmakers, would heed the astronomical landmarks! Lunar eclipses, he says, which may occur as often as once every six months, provide the means for anchoring whole strings of locations east or west of each other at a stroke. Unfortunately, as Ptolemy notes, this potential boon to cartography has gone untapped for the past five hundred years—since the lunar eclipse of September 20 in 331 B.C., when Alexander the Great met Darius of Persia on the battlefield. Observers sighted that memorable eclipse over Carthage at the second hour of the evening, and farther east in the Assyrian metropolis of Arbela at the fifth hour, from which facts Ptolemy (correctly) establishes the distance between the two cities as 45 degrees of longitude.*
To gauge latitudes north or south of the equator, Ptolemy counts the stars—those that rise and set over a given region at different times over the course of the year, those that neither rise nor set but always appear as darkness falls, and those that never come into view, though they be well known elsewhere. On the Island of Thulē (Shetland Islands), for example, far up at 63 degrees north, where the longest day lasts a full twenty hours, no one sees the mid-summer return of the Dog Star that marks the flooding of the Nile in Egypt.
Ptolemy assumes the world to measure 18,000 miles around. His predecessor Eratosthenes had figured the earth’s circumference at a more generous 25,000 miles in 240 B.C., by comparing shadow lengths in two cities along the Nile on the day of the summer solstice, but Ptolemy favors the more recent work of Poseidonius, about 100 B.C., who observed the stars to shrink the globe.
Ptolemy’s Geographia offers instructions for creating globes as well as flat map projections. However, the “known world,” as Ptolemy calls it—or “the inhabited world” or “the world of our time”—occupies only half a hemisphere. From the Islands of the Blest off the west coast of Africa, it stretches eastward all the way through “India Beyond the Ganges” to “Sera,” where the Silk Road ends, and south from the “lands of the unknown Skythians,” near t
he Baltic, to the junction of the Blue Nile with the White. Beyond those borders of familiarity, Ptolemy’s depiction of lower Africa widens into blank spaces as the continent approaches the Equator, then fans out at the Tropic of Capricorn into a vague undiscovered country, spreading down and across the southern limit of the map, and rising to meet China at the far eastern margin of the Indian Ocean. It is an entirely landlocked world, with all bays and seas surrounded by empires and satrapies, for none of Ptolemy’s sources has ventured far enough by vessel to realize the water’s true extent.
“In all subjects that have not reached a state of complete knowledge,” Ptolemy says in Geographia, “whether because they are too vast, or because they do not always remain the same, the passage of time always makes far more accurate research possible; and such is the case with world cartography, too.”
The passage of one thousand years changes the shape of the world map from Ptolemy’s vision to a circle centered on Jerusalem. Now Heaven imposes a new focus on geography, directing pilgrims and Crusaders to the Holy Land. Although Ptolemy had oriented his globe with North at the top, the new world, as viewed by the Catholic Church, has taken a quarter-turn counterclockwise, leaving East uppermost instead.
This widespread image, the medieval “mappa mundi,” is divided into three unequal parts, one for each of Noah’s sons: Asia fills the top half, while Europe and Africa stand side by side in the bottom. The borders of the three lands suggest a “T” inscribed inside an “O,” since the lower length of Asia bisects the circle along its diameter, and the Europe-Africa boundary divides the lower hemisphere in half. At the junction of these two brushstrokes sits Jerusalem.
In lieu of places arranged by latitude and longitude, the mappa mundi gives a global overview overlaid with scrambled bits of knowledge concerning this world and the next. The example installed at England’s Hereford Cathedral around the year 1300 locates the Gates of Paradise, the Tower of Babel, the Ark at rest in Armenia, and the place where Lot’s wife changed into a pillar of salt. It situates forty mythical and actual animals near their natural habitats and describes them in accompanying legends, including centaur, mermaid, unicorn, “giant ants” that “guard sands of gold,” and the lynx that “sees through walls and pisses black stone.” Stranger still are the map’s fifty “monstrous” races of man—the Arimaspi who “battle Griffins for emeralds,” the Blemyae with their mouths and eyes in their chests. Few of these foreigners display Christian or even human virtues, and only the Corcina people of Asia recall Ptolemy’s geography lessons of old, for their shadows are said to “fall north in winter, south in summer,” meaning they live in the tropics.
A single hemisphere still suffices to support the whole world population of the mappa mundi. Around its circumference a great ocean rims the lands in view and presumably flows all around the back. The mappa mundi may appear a flat disk rendered on vellum, but it represents a globe. The challenge for Christopher Columbus will not be to convince his critics of the earth’s roundness, but rather that it is smaller than they imagine.
Columbus clings to Ptolemy’s belief in a world with a girth of merely 18,000 miles, though he knows that Portuguese navigators estimate it to be at least 24,000. Defying them, Columbus wagers he can cross the unknown waters before his crews die of hunger or thirst.
Officially, as Columbus acknowledges in his log, he leads a religious mission, “In the name of Our Lord Jesus Christ,” sent by the “most Christian, exalted, excellent, and powerful princes,” the King and Queen of Spain, “to the regions of India, to see the Princes there and the peoples and the lands, and to learn of their disposition, and of everything, and the measures which could be taken for their conversion to our Holy Faith.”
Given his prior experience of the sea and his interest in geography, Columbus vows to press his unique situation: “I propose to make a new chart for navigation, on which I will set down all the sea and lands of the Ocean Sea, in their correct locations and with their correct bearings. Further, I shall compile a book and shall map everything by latitude and longitude. And above all, it is fitting that I forget about sleeping and devote much attention to navigation in order to accomplish this.”
At the same time, Columbus must quell the fears of the ninety-some roustabouts and officers who accompany him on the three ships.
“This day we completely lost sight of land,” he reports on Sunday, September 9, 1492, “and many men sighed and wept for fear they would not see it again for a long time. I comforted them with great promises of lands and riches. To sustain their hope and dispel their fears of a long voyage, I decided to reckon fewer leagues than we actually made. I did this that they might not think themselves so great a distance from Spain as they really were. For myself I will keep a confidential accurate reckoning.”
When Columbus makes landfall in the Caribbean, nothing he discovers among the islands dispels his fixed idea that he has reached India:
“The woods and vegetation are as green as in April in Andalucía, and the song of the little birds might make a man wish never to leave here,” he writes on October 21. “The flocks of parrots that darken the sun and the large and small birds of so many species are so different from our own that it is a wonder. In addition, there are trees of a thousand kinds, all with fruit according to their kind, and they all give off a marvelous fragrance. I am the saddest man in the world for not knowing what kinds of things these are because I am very sure that they are valuable. I am bringing a sample of everything I can.”
To be sure, Columbus is no naturalist, yet he cites the parrots over and over. The green and purple birds, identified on mappae mundi as the product of India, testify he has indeed arrived somewhere near his intended destination. The “mainland” the natives describe at a distance of perhaps ten days’ journey must be India. The island they call Cuba, he concludes on October 27, the day before he lands there, is just “the Indian name for Japan.”
In his own choice of place names, Columbus honors his Savior and his sovereigns: San Salvador, Santa María de la Concepcíon, Ferdinandina, Isabela. Dubbing his way through the archipelago, he is barred from a full tour of the region by the grounding of one ship and attempted mutiny aboard another.
On his way home to glory, a February storm blows out of the sea with the force of the Devil. Columbus, fearful the water will swallow him before he can declare his discoveries to the Crown, now draws his chart. He secures the parchment in a waxed cloth, seals the cloth inside a barrel, and throws the barrel to the waves. Should he perish, the finder of his message may inform the Sovereigns “how Our Lord has given me victory in everything I desired about the Indies.”
Instead, the map disappears in the storm while its maker lives to command three more westward voyages as Admiral of the Ocean Sea and Viceroy of the Indies. Through all these explorations, Columbus never concedes he has found anything but a shortcut to the Orient. Only after his death, as his remains traipse back and forth across the Atlantic yet again for a second and even a third burial, does the magnitude of his discovery divide the globe into the Old World and the New.
Slowly the outline of the far shore takes form. The piece labeled “Florida” hangs unattached, floating like a shroud above Columbus’s Hispaniola (Haiti and the Dominican Republic), until the ends of the Floridian borderlines connect to a larger landmass. “America” appears for the first time on a wide new world map in 1507. The territory borrows the Christian name of its frequent visitor Amerigo Vespucci, an Italian merchant and navigator. Vespucci has sailed west with both the Portuguese and the Spanish, riding the rivalry between them, boldly proclaiming their scattered claims a bona fide continent distinct from Asia.
At first Vespucci’s first name applies only to the southern half of the New World, but it comes to envelop the northern part as well, as explorers from competing countries push ahead to see what lies beyond.
The Spanish throne wins a great victory when Vasco Núñez de Balboa falls to his knees on a bare summit of Panama in
September 1513, exulting at first sight of the Pacific Ocean. It takes him several days to descend from his encampment through the forest to the shore, where he wades into the water to baptize it. Sword drawn and shield held high, Balboa shouts the name of Spain over this sea and every land washed by it, as though he already knows it bathes half the world.
In 1520, Ferdinand Magellan ventures with five Spanish ships into the Pacific, and measures its width in hardship:
“We were three months and twenty days without getting any kind of fresh food,” Magellan’s Italian navigator, Antonio Pigafetta, writes of the crossing. “We ate biscuit, which was no longer biscuit, but powder of biscuits swarming with worms, for they had eaten the good. It stank strongly of the urine of rats. We drank yellow water that had been putrid for many days. We also ate some ox-hides that covered the top of the mainyard to prevent the yard from chafing the shrouds, and which had become exceedingly hard because of the sun, rain, and wind. We left the hides in the sea for four or five days, and then placed them for a few moments on top of the embers, and so ate them; and often we ate sawdust from boards. Rats were sold for one half-ducado apiece, and even then we could not get them.”
In the heat of this age of exploration, in 1543, a Polish cleric publishes a book that moves the entire world to a new locale. De Revolutionibus, by Nicolaus Copernicus, plucks the earth from its stationary post at the hub of the celestial spheres, and sets it spinning around the Sun, between the orbits of Venus and Mars. The strangeness and unpopularity of Copernicus’s opinion nearly silence it, but within one hundred years, against all expectation, the Sun takes over the center of the universe, and our world voyages as a wandering star.
Doesn’t this new planet deserve a name? If Champlain can christen his lake and Hudson his bay, why must the newly mobile globe labor under an old, inaccurate term? “Earth” recalls the ancient division of all ordinary matter into four elements—earth, water, air, fire—and the designation of earth as the heaviest, least heavenly among them. In that scheme, water flowed over earth, air floated above both, and fire rose through air to the threshold of the celestial spheres, where planets and stars embodied a fifth element—quintessence. With world order shifting on maps of the heavens, might not “the earth” take a proper name from mythology? But already it is too late to dislodge the old name, too late even to change it from “earth” to “water,” now that seas can be seen to yawn and stretch in all directions.
